Although many tribes migrated through the Yellowstone region, only one tribe made it their permanent home. This was a small, very reclusive band of Shoshone, who called themselves the Sheepeaters. There are various spellings of the name in their native language, but the one I went with in the Yellowstone Romance Series is Tukudeka. I believe the actual translation means "eaters of meat". The Shoshone bands tended to identify themselves by their diet and region of habitation. The Tukudeka were primarily hunters, and perfected the art of hunting bighorn sheep in Yellowstone.
There are still many archaeological sites in the park, giving evidence to their existence in Yellowstone. They lived in small family groups, not large tribes, and were known for their amazing hide tanning ability, and creating hunting bows made from elk antlers and bighorn sheep horns. The process to make these bows took months, and included soaking the horn in hot springs to soften them to make them bendable. These bows were highly prized, and rarely traded with other tribes.
Daniel Osborne, the leading man in Yellowstone Heart Song, was raised by a group of Sheepeaters, and I have tried to depict their lives and customs in this book, as well as the next installment, Yellowstone Redemption. My main source of information came from a book called Mountain Spirit: The Sheepeater Indians of Yellowstone.
Last summer, while on a hike to see Sheepeater Cliffs, we sort of went off trail a bit, or at least the trail was hardly used, making it less obvious (not recommended, by the way, if you're not wearing sturdy shoes. The rocks and cliffs and boulders we climbed over had me wondering how all four of us made it out of there without a sprained ankle) along the Gardner River. Suddenly we stood at the top of a large cascade/waterfall. Nowhere on a park map was this identified. To satisfy my curiosity, I consulted a book called Yellowstone Waterfalls and their Discoveries. Turns out this falls was un-named by the park, but the authors of the book named it Tukuarika Falls (another variation of the spelling for Sheepeaters).